The problems addressed herein relate to operating a handheld device, such as a smartphone or tablet comprising a touchscreen, with a single hand. The issues are particularly acute for a class of devices which exceed a certain size, colloquially termed ‘phablets’. Such devices have a form factor between that of a smartphone and that of a tablet. The form factor was popularized by Samsung's Galaxy Note and now has many examples, including the Apple iPhone 6 Plus. Phablets are defined by their size, with the Samsung Galaxy Note (5.3 inch screen size) and iPhone 6 Plus (5.5 inch screen size) being typical of the genre.
Despite their large size, users often still wish to operate, i.e., to hold and control, phablet-size devices in the same way they do with smartphones having a smaller size, which is holding the device and operating the touchscreen using the same hand, herein also referred to as single-handed operation. This may be achieved by manually shifting the position of the device within the hand using a ‘shuffle’ motion, thus moving the ‘touch finger’ closer to a region of the screen which the user intends to touch. For instance, users may use one finger (most often the middle finger) placed on the rear face of the device to hold the device steady, and then rock or tilt the device using other fingers (most often the first and a combination of the fourth and the little finger) to allow the touching finger (most often the thumb) to touch the screen. Alternatively, users may use the second or the fourth finger on the rear face of the device to hold the device, and these fingers plus the little finger, which is placed on the bottom side of the device, rock the device back and forth whilst the touchscreen is operated by the thumb. However, moving the device in this manner requires a level of dexterity to perform without dropping the device. Even when performed safely, it is a slow and frustrating user interaction.
It is physically difficult for most people to operate a phablet-size device in a stable manner, i.e., to statically hold the device with a single hand and being able to reach all areas of the touchscreen to control the device. Unstable operation of the device may lead to either difficulty in interacting with the touchscreen or, in the worst case, dropping the device. Hence, solutions are required to enable single-handed operation of such devices.
A known solution is the use of a user-interface control which ‘shifts’ the user interface displayed on the touchscreen such that user-interface elements at the top of the screen come within reach of the touching finger, such as Apple's ‘Reachability’ one-hand mode. However, these solutions suffer from being less intuitive for users, in addition to reducing the usable screen size.